ABSTRACT

A field experiment was conducted in 2018–2020 to investigate the effect of two nitrogen application rates (N₀ = 0 kg ha⁻¹(control), N₉₀ = 90 kg ha⁻¹, and N₁₈₀ = 180 kg ha⁻¹) on morphological and physiological behaviours of two new rapeseed varieties; V₁ = JYJS01 (semi-dwarf variety) and V₂ = CY36 (tall variety). Our results indicated that N application enhanced the plant growth and seed protein content in comparison to control. Contrastingly, compared with control, sugar contents, i.e. sucrose and reducing sugars, decreased significantly in response to an increase in N. Seed oil content also decreased by 8.5% and 5.5%, 6.7% and 3.9% against N₁₈₀ in V₁ and V₂ during 2019 and 2020, respectively. Furthermore, higher nitrogen application rates decreased seed fatty acid proportions by decreasing the sugar availability for fatty acid biosynthesis. Our results demonstrated the highest seed yield (9.4 g plant⁻¹ in 2018/19 and 9.5 g plant⁻¹ in 2019/20) in V₂ against N₁₈₀, and the lowest seed yield (3.2 g plant⁻¹ in 2018/19 and 3.4 g plant⁻¹ in 2019/20) in V₁ at control. These findings imply that a high nitrogen application rate had increased the yield. At the same time, the carbohydrates translocation from stems to seed for fatty acid biosynthesis decreased, which played their significant role in seed physiology for fatty acid metabolisms, ultimately affected the seed quality. However, there is still a dire need to evaluate how nitrogen application affect the carbohydrate availability for fatty acid metabolism in the seed of new winter rapeseed varieties.

摘要

2018-2020 年进行了一项田间试验，以研究两种施氮量（N ₀  = 0 kg ha ^-1（对照）、N ₉₀  = 90 kg ha ^-1和 N ₁₈₀  = 180 kg ha ^-1）的影响两个油菜新品种的形态和生理行为；V ₁  = JYJS01（半矮化品种）和 V ₂ = CY36（高品种）。我们的结果表明，与对照相比，施氮提高了植物生长和种子蛋白质含量。相反，与对照相比，糖含量，即蔗糖和还原糖，随着N的增加而显着下降。V ₁和V中的种子油含量相对于N _{180也分别下降了8.5%和5.5%、6.7%和3.9%。 2}分别在 2019 年和 2020 年期间。此外，较高的施氮量通过降低脂肪酸生物合成的糖利用率来降低种子脂肪酸的比例。我们的结果表明，V ₂对 N的种子产量最高（2018/19 年为 9.4 g 植物^-1和 2019/20 年为 9.5 g 植物^{-1 ）}₁₈₀和在对照的 V ₁中的最低种子产量（2018/19 年为3.2 g 植物^{-1和 2019/20 年为 3.4 g 植物-1} ） 。这些发现表明高施氮量增加了产量。同时，用于脂肪酸生物合成的碳水化合物从茎到种子的转运减少，这在脂肪酸代谢的种子生理中发挥了重要作用，最终影响了种子的质量。然而，仍然迫切需要评估施氮如何影响新冬油菜品种种子中脂肪酸代谢的碳水化合物可用性。